1. Field of the Invention
The invention relates to an openable motor vehicle roof with a front movable roof element which is movably supported on side roof rails and which, in the closed position of the roof, can be placed against an apron or the like.
2. Description of Related Art
Published European Patent Application EP 0 755 815 A1 discloses a folding roof for motor vehicles which has a folding convertible top for selectively closing or at least partially clearing a roof opening which is made in the fixed roof surface; the front end of the top, in the form of a front end bow, forms a roof peak which is adjustably guided along guide rails which run in the lengthwise direction of the motor vehicle, and in the closed position of the roof, is pressed with its front edge against a roof-mounted abutment. On each of the guide rails, a respective carriage is guided which is permanently connected to a drive cable and which is coupled via a pivot lever to the front end of the roof peak. The pivot lever is guided on a guideway of the guide rail such that, in the displacement area of the folding roof, between the open position and an intermediate position near the closed position, it executes purely translational motion, and in the area between the intermediate position and the closed position, it executes a combined translational and rotational motion. By rotating the pivot lever, the roof peak, which is raised with its front edge and which rests on the carriage on its back end, is lowered on its front end and pressed against a contact surface or a frame seal of the roof frame with high force by the combined translational and rotational motion. The pivot lever, on the one hand, controls the raising or lowering motion of the front edge of the roof peak by its engagement in the guideway, and on the other hand, applies the force for pressing the front edge of the roof peak to the latter. In this combined mechanism, the defect is that the front edge of the roof peak, when the convertible top is opened, is immediately lifted and raised almost vertically so that the airstream can be captured in it. In addition, the raised front edge adversely affects the visual appearance.
A primary object of the present invention is to devise an openable motor vehicle roof of the initially mentioned type which has an improved movement mechanism in regard to the opening and closing of the front roof element in the vicinity of the apron.
Another object of the invention is to develop the initially mentioned openable motor vehicle roof with at least one intermediate bow which is movably supported on the side roof rails such that an improved motion sequence is ensured when the front roof element and the intermediate bow are moved.
The initially mentioned object is achieved as in accordance with the invention in that the roof element is guided by a guide means which is supported on the guide rails of the side roof rails in the opening and closing process from or to the apron such that the front edge of the roof element is moved essentially tangentially to the outside roof skin. The front edge of the front roof element is pressed by its essentially tangential motion when the roof is closed from the rear against the apron and especially against the apron seal, being moved on or near the roof contour, and thus, not forming a significant projection in which the airstream can be caught. Essentially tangential motion is also defined as motion with a comparatively small slope with reference to the outside roof skin. In this motion, the front edge of the roof element is always kept lower than its rear edge. Thus, these movements, which can be accomplished by the guide means, differ fundamentally from the upwardly directed pivoting motion of the front edge of the roof element around the rear pivot axis according to the initially mentioned prior art. Instead of an apron, there can be any transverse part which is located on the body or on the top edge of the front window and which is suited for tight contact with the roof element, a seal being feasibly attached to this transverse part.
Preferably, the guide means, in a further opening process, lifts a rear edge of the front roof element relative to its front edge. In this way, the roof element is tilted around the transverse axis in the manner of a spoiler. During further translational motion of the roof element to the rear, it can be moved in its oblique position at least partially over the nearest movable roof element, for example, an intermediate bow, and can be moved with it in a compact arrangement into a rear lowered position. When the roof element is raised, at the same time, the front edge is raised along a path segment from a sealing flange which runs on the outside on the side roof rail so that freedom is ensured for the continuing displacement motion of the roof element.
The motion of the front edge of the roof element can be controlled, for example, in an openable fixed roof which has a sliding roof or a louvered roof for selectively closing or at least partially clearing a roof opening on a path of movement which is essentially parallel to the guide rail. In other forms of roofs, for example, in the folding roof of a convertible, in one advantageous embodiment, according to the curvature of the roof and the formation of the side roof rails, the motion of the front edge of the roof element, which edge is tilted at an angle or is essentially tangential to the outside roof skin, can take place nonparallel to the guide rail.
One preferred embodiment calls for the guide means to have a four-bar mechanism by means of which the roof element is supported to be able to pivot on a carriage which is supported to be able to move lengthwise on the guide rail by a drive, and for the control lever of the four-bar mechanism engaged to the control crank to swing the roof element during the lengthwise displacement of the carriage. The four-bar mechanism can be adapted for any form of the roof and can be designed for a certain motion sequence. It is simple and durable and offers high operating safety.
The control crank is feasibly located on the side roof rail and is formed especially on the guide rail.
The initially mentioned object is achieved in that the roof element is supported by a guide means on the guide rails of the side roof rails, the guide means each having a four-bar mechanism by means of which the roof element is movably supported on a carriage which can be moved on the guide rail, and that a control lever of the four-bar mechanism controls the motion of the four-bar mechanism and of the roof element especially in the opening or closing motion away from or to the apron depending on the position of the carriage to the guide rail. The four-bar mechanism enables adjustment of different motion sequences of the roof element in the vicinity of the apron, for example, initial motion of the front roof element which is largely tangential to the outside roof skin in the area of the apron. On the other hand, spoiler-like raising of the roof element can also take place.
In one preferred embodiment of the invention, there is a support device for fixing the front roof element on the apron; this device has at least one support unit which is located on the apron and on the roof element, and which has an oblong support part which projects in the direction of motion of the roof element and an assigned support part receiver. The support device offers vertical centering of the front roof element in its closed position on the apron between the outer bearings of the roof element on the side roof rails. At least one support unit is preferably located in the middle area of the apron or of the roof element so that it can direct the wind forces acting on the roof element and the sealing forces largely normally to the support part on the apron. Thus, the wind load or the sealing force is applied directly to the apron.
The support device forms an additional, simply built passive support without movable elements. The front roof element can be made in a lightweight structure with low tolerance requirements by means of the support. A certain flexibility of the roof element is thus allowable since the roof element is moved flush to the apron in its correct form by the support device and by the closing forces. Thus, the production tolerances can be equalized by the support. When several support units are used, optimum adaptation to the apron can be achieved.
Feasibly, the projecting support part is located on the apron and the support part receiver is located on the roof peak. To largely preclude the danger of injury by the projecting support part, it is advantageous if a protective bead is located on the inside of the motor vehicle adjacent to the support part. The protective bead sufficiently covers the support part and is made especially with extensive rounding which prevents injuries in the case of impact of the passengers. Preferably, the projecting support part is a support tongue located on the apron or a pin.
The second object is achieved by the intermediate bow being fixed on the guide rail of the respective side roof rail, in the closed position of the roof, by the front roof element releasing the intermediate bow in its opening motion and entraining it into a rear position, and by the front roof element being moved by a drive part which is movably supported on the guide rail and which controls coupling and de-coupling. Folding of a folding roof can be controlled by the forcibly controlled fixing and moving of the shaped parts of the roof, such as the front roof element and the intermediate bow, so that larger, untensioned fabric surfaces of the folding roof which could cause fluttering of the roof can be avoided.
Preferably, the bearing means of the intermediate bow has a locking means with which the intermediate bow can be fixed by controlling the drive part on the guide rail, or can be fixed on the front roof element after unlocking from the guide rail.
The locking means can be a locking block arrangement which contains a spring-loaded blocking element which can be actuated especially by the drive part and which controls the unlocking of the intermediate bow from the guide rail.
The front roof element of the motor vehicle roof in accordance with the invention can be the roof peak of a folding roof, especially of the folding roof of the folding top of a convertible, a louvered roof element or the cover of a sliding and lifting roof.
One embodiment of the motor vehicle roof is explained in detail below with reference to the drawings.